Gary Cook Reservoir Report
Nearby: Shadow Lake Dam Grindstaff Dam
Last Updated: December 6, 2025
Gary Cook is a private earth dam located in Marble Hill, Missouri, designed by the USDA NRCS with a primary purpose of flood risk reduction.
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Summary
Completed in 1997, this dam stands at a height of 30.5 feet and has a storage capacity of 132 acre-feet. It serves multiple purposes including flood risk reduction, grade stabilization, and recreation, with a low hazard potential and a moderate risk assessment rating.
Situated along Cedar Branch in Bollinger County, Gary Cook spans 434 feet in length and covers a surface area of 4 acres. Its uncontrolled spillway has a width of 15 feet, and the dam has a drainage area of 172.8 square miles. Despite being of stone core type with a soil foundation, the dam has not been rated for condition assessment and last underwent inspection in November 1999. With no associated structures and no outlet gates, the dam remains under private ownership and is not regulated by the state.
For water resource and climate enthusiasts, Gary Cook presents an intriguing case study in dam engineering and management. From its construction by the Natural Resources Conservation Service to its role in flood risk reduction and recreational activities, this earth dam in Missouri offers valuable insights into the complexities of maintaining infrastructure for water management purposes. As discussions around climate change and water resource sustainability continue to evolve, understanding the design, function, and condition of structures like Gary Cook is crucial for ensuring the safety and resilience of our water systems.
Year Completed |
1997 |
Dam Length |
434 |
Dam Height |
30.5 |
River Or Stream |
CEDAR BRANCH |
Primary Dam Type |
Earth |
Surface Area |
4 |
Hydraulic Height |
30 |
Drainage Area |
172.8 |
Nid Storage |
132 |
Structural Height |
38 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
38 |
Seasonal Comparison
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Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Gary Cook